Animation Variable Not Assigned?

Hello, I am trying to get one animation to play using mechanim so I made a trigger named Shoot and added it to the transition from anystate. I get an error saying that I need to assign the anim variable of the PlayerAnimator script in the inspector. But, when I go to the scrip in the inspector there is no variable slot for the anim. Here is my code, I followed a Unity tutorial.

 using UnityEngine;
 using System.Collections;
 
 public class PlayerAnimator : MonoBehaviour {
 
 
     Animator anim;
     int shoot = Animator.StringToHash("Shoot");
 
     // Use this for initialization
     void Start () {
         anim = GetComponent<Animator>();
     }
 
     // Update is called once per frame
     void Update () {
 
     }
 
     public void Shoot()
     {
         anim.SetTrigger (shoot);
     }
 }